1,413 research outputs found
Ambiguity-Aware Multi-Object Pose Optimization for Visually-Assisted Robot Manipulation
6D object pose estimation aims to infer the relative pose between the object
and the camera using a single image or multiple images. Most works have focused
on predicting the object pose without associated uncertainty under occlusion
and structural ambiguity (symmetricity). However, these works demand prior
information about shape attributes, and this condition is hardly satisfied in
reality; even asymmetric objects may be symmetric under the viewpoint change.
In addition, acquiring and fusing diverse sensor data is challenging when
extending them to robotics applications. Tackling these limitations, we present
an ambiguity-aware 6D object pose estimation network, PrimA6D++, as a generic
uncertainty prediction method. The major challenges in pose estimation, such as
occlusion and symmetry, can be handled in a generic manner based on the
measured ambiguity of the prediction. Specifically, we devise a network to
reconstruct the three rotation axis primitive images of a target object and
predict the underlying uncertainty along each primitive axis. Leveraging the
estimated uncertainty, we then optimize multi-object poses using visual
measurements and camera poses by treating it as an object SLAM problem. The
proposed method shows a significant performance improvement in T-LESS and
YCB-Video datasets. We further demonstrate real-time scene recognition
capability for visually-assisted robot manipulation. Our code and supplementary
materials are available at https://github.com/rpmsnu/PrimA6D.Comment: IEEE Robotics and Automation Letter
Real quadratic fields admitting universal lattices of rank7
In this paper, we will prove that if is sufficiently large square-free
positive rational integer, then there is no integral septenary universal
quadratic lattice over where
A past adapts to the future : an old Japanese city will adapt to the future with preserving its past
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture; and, (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1990.Includes bibliographical references (leaves 151-157).Over the last quarter of a century, historic preservation has become a major component of urban revitalization in the US. Along with the cultural and economic benefits, the restoration of historic structures and environments has also produced a distinct improvement in the quality of life in several American cities. Japan, on the other hand, has only recently begun to recognize the potential contribution of historic preservation to urban revitalization; and, in general, its recent revitalization efforts, especially in several small cities, have not been well formulated or well executed. It is proposed here that small, declining Japanese cities can be revitalized, both economically and culturally, by making effective use of their historic resources. The concept of historic preservation as an urban revitalization tool is first discussed with emphasis on several major theories of preservation in an urban setting. Next, actual instances in which historic preservation was successfully integrated into urban revitalization programs are analyzed. Finally, a revitalization strategy for Otaru, a small declining city in northern Japan, is formulated based on the Urban Cultural Park concept implemented in the city of Lowell, Massachusetts.by Myung-hwan Kim.M.C.P.M.S
Current-Induced Resonant Motion of a Magnetic Vortex Core: Effect of Nonadiabatic Spin Torque
The current-induced resonant excitation of a magnetic vortex core is
investigated by means of analytical and micromagnetic calculations. We find
that the radius and the phase shift of the resonant motion are not correctly
described by the analytical equations because of the dynamic distortion of a
vortex core. In contrast, the initial tilting angle of a vortex core is free
from the distortion and determined by the nonadiabaticity of the spin torque.
It is insensitive to experimentally uncontrollable current-induced in-plane
Oersted field. We propose that a time-resolved imaging of the very initial
trajectory of a core is essential to experimentally estimate the
nonadiabaticity.Comment: 4 pages, 4 figure
Structural and optical properties of ZnO nanorods by electrochemical growth using multi-walled carbon nanotube-composed seed layers
We reported the enhancement of the structural and optical properties of electrochemically synthesized zinc oxide [ZnO] nanorod arrays [NRAs] using the multi-walled carbon nanotube [MWCNT]-composed seed layers, which were formed by spin-coating the aqueous seed solution containing MWCNTs on the indium tin oxide-coated glass substrate. The MWCNT-composed seed layer served as the efficient nucleation surface as well as the film with better electrical conductivity, thus leading to a more uniform high-density ZnO NRAs with an improved crystal quality during the electrochemical deposition process. For ZnO NRAs grown on the seed layer containing MWCNTs (2 wt.%), the photoluminescence peak intensity of the near-band-edge emission at a wavelength of approximately 375 nm was enhanced by 2.8 times compared with that of the ZnO nanorods grown without the seed layer due to the high crystallinity of ZnO NRAs and the surface plasmon-meditated emission enhancement by MWCNTs. The effect of the MWCNT-composed seed layer on the surface wettability was also investigated
Towards Optimal Decoding for Polar Codes
In the conventional successive cancellation (SC) decoder for polar codes, all
the future bits to be estimated later are treated as random variables. However,
polar codes inevitably involve frozen bits, and their concatenated coding
schemes also include parity bits causally generated from the past bits
estimated earlier. We refer to the frozen and parity bits located behind a
target decoding bit as its future constraints (FCs). Although the values of FCs
are deterministic given the past estimates, they have not been exploited in the
conventional SC-based decoders, not leading to optimality. In this paper, we
propose SC-check (SCC) and belief-propagation SCC (BP-SCC) decoding algorithms
in order to leverage FCs in decoding.We further devise a tree search technique
based on stack-based backjumping (SBJ) to solve dynamic constraint satisfaction
problems (CSPs) formulated by FCs. Over the binary erasure channel (BEC),
numerical results show that a combination of the BP-SCC algorithm and the SBJ
tree search technique achieves the erasure recovery performance close to the
dependence testing (DT) bound, a bound of achievable finite-length performance
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